Just for interest to those ppl thinking of upgrading their ECU's. When I was at uni a guy was doing his thesis on fuel injectors for the motorsport team. A summary of what he was doing is below:

Most injectors work by jetting a single 'pencil stream' or thin jet of fuel down the intake runner so that it hits the back of the valve or side of the runner. The impact with the valve makes the fuel 'splash' into small droplets and get sucked in with the air.

There are variations such as twin spray injectors (for 2 intake valve engines).

But then there are these other type of injectors. Then have 4 or more ports on the bottom and generate a 'mist' as apposed to a stream. The advantage of this is that the mist has much finer particules, it also evaporates more readily, cools the intake charge and burns evenly. Also fuel is less likely to stick to the sides of the intake runner.

The ones he was testing were fitted standard to a honda F4i (CBR 600) engine. And apparently made a few KW difference (on a 600CC engine!)

Has anyone seen anything like this for 4.0L sized engines?
Or any experience with any of these?

I was under the impression that all injectors used in the last few years are mist, but I have no facts to support this statement so shoot me down if you will.

I was actually thinking about trying something along these lines with water. I know it's used primarily in forced induction motors for different reasons, but even in my NA car I notice an improvement when driving in fog, so I thought I'd try using one of those ultrasonic mist/fog generators patched inline between the throttle body and the air box. It'd probably need a few transducers to get any benfit but even a proper water injection system with my high compression (12.5:1) engine would probably help out anyway

Water injection has been used to a fair bit of success on N/A engines.

Benefits are threefold.... 1) Cools intake temp. Now i know this is being discussed in another thread so you are aware of the advantages here. This is how my very basic system works - at 3psi a pump is activated which simply sprays a mist in front of the blower intake.

2) The water coming in through such a dry system effectively "dirties" the air charge and thus increases resistance to detonation, having a similar effect to increasing the octane of the fuel.

3) Once it starts burning, water assists the combustion process. As it is burnt, releases more oxygen into the combustion chamber (hey - all it is is 2 hydrogen molecules and 1 oxygen atom) which means the fuel burns more efficiently towards the end of the combustion process. Altho this is probably something which the engine needs to be 'tuned' to.... in fact ive read stories of people replacing up to 50% of their fuel with water....

/me goes and emptys 20l or water into my fuel tank

What's the link to the other thread ?
I missed it actually...

Well I haven't seen these pencil spray pattern injectors yet,(I have seen old articles about them), and I can say I have cleaned and tested more than a few different types (Ford and Jap etc), most have a similar standard spray pattern, easy to see it when doing a balance and flow test.

I have some new 42lb/hr ford racing/bosch injectors with the multiple spray pattern.
Shane

There are basically 2 types of injectors available, disc and pintle. The pintle tends to produce a more concentrated "garden hose" stream which becomes more pronounced as the pressure is increased. It is actually not recomended to increase the base fuel pressure due to that problem. The disc injector usually has 4 holes in the end and produces a finer spray pattern which does not get affected as much with pressure increases.

Lucas is a manufacturer of disc and Bosch does both but more of the pintle style.